A radio access network (RAN) is a part of a mobile communication system that implements radio access technology. That is, a RAN is a portion of a communication network that connects mobile devices to a core network (CN). One or more bearers (e.g., discrete communication connections) can be established between a RAN and mobile device. One or more distinct flows of information can be conveyed over each bearer. Some mobile devices are able to concurrently connect to multiple RANs at the same time.
At present in a 3rd Generation Partnership Project (3GPP) network, connectivity between a mobile device and a RAN is enabled by at least a default bearer. When this bearer (or any other bearer) is lost, the mobile device is no longer able to communicate with the core network over the lost bearer. Conventional 3GPP networks effectively monitor the dedicated bearer for a loss of coverage (or performs this function through some mechanism: for example, LTE monitors a Layer 2 (L2) state to determine attachment), which if it occurs an assumption is made that the mobile device experiences an RF loss. The network may attempt to “pass-off” all the bearers established between the mobile device and the RAN to an alternative network in response. Moving the bearers of the mobile device from one RAN to another is an all-or-nothing process. Even if one bearer (assuming multiple bearers connect a RAN and mobile device and assuming a default bearer is lost) is operating fine, all communications between the mobile device and RAN are moved. It should be appreciated that a mobile device can be concurrently connected to multiple RANs at a time, and that only bearers connecting the mobile device to a single RAN (the one where the default bearer was lost) are affected by the “pass-off”.